All About Brake Fluid!

Brake fluid makes a huge impact on your brake performance, so don't cheap out with cheap fluid from the auto parts store! Cheaper fluids may not be compatible with some aftermarket motorcycle brakes, plus using a higher quality racing brake fluid will make a noticeable difference! Aggressive riders and racers can use their brakes more aggressively less brake fade, and the average street rider should notice their brakes will work better for longer periods between fluid flushes. It's easy to exceed the performance of cheap fluid, so paying $20 or more for a bottle of high-quality, high-temp fluid makes for a much better and safer brake system.



Breakdown and Moisture Contamination
Brake fluid is hydroscopic so it absorbs water/moisture from the atmosphere once removed from it's original sealed container. Over time the water content will rise and the fluid becomes less effective. This happens to fluid that is in your motorcycle's brake system, as well as the leftover fluid in the bottle. It's also something that happens once it's removed from the original sealed container and continues over time.

Your leftover bottle of fluid will start to absorb more fluid as time goes by, thus reducing the effective boiling point when you need the next time. Most manufacturers specify a 1 year shelf life of containers that have been opened and partially used. Humid climates will drastically reduce that timeframe. To be on the safe side, only use an open bottle during your current riding season and chuck it at the end of your season! Always store in the original container with the cap screwed on tightly and always dispose of old fluid responsibly.

The fluid in your brake system will do the same thing, but it's made worse when combined with high temps or heavy brake use. Flush your brakes at the beginning of every riding season! In trackday/racing conditions, fluid will break down sooner and require more frequent flushing.


Boiling Points
Knowing the boiling point of fluid will help you choose a quality brake fluid. The higher quality race fluids tend to have 600 degree boiling points, with some even higher than that! That boiling point starts to lower over time due to the fluid absorbing moisture as well as the breakdown from heat, and this is why you need to periodically flush your brake fluid.

The boiling point is specified as "dry" or "wet". Dry refers to brand new fluid from a freshly opened container, while wet refers to fluid that has absorbed 3.7% water. Safety standards require the fluid to have a stated minimum boiling point for both dry and wet. This will give you an idea of the boiling point of your fluid when it's brand new as well as after it's been in use (or in an open bottle).



DOT Ratings
Most motorcycle brake systems are designed to use DOT 4 or DOT 5.1 fluid. HOWEVER, pay close attention to your brake components so that you use the correct fluid type. Some aftermarket brake components (like Beringer) come with special seals that are only compatible with DOT 4 fluid, and other fluid types can cause damage to those special seals.



Brake Fluid For Supermoto
Fluid makes a big difference for any bike, but especially converted supermoto bikes that use the stock caliper and master cylinder. Asphalt riding naturally requires more front brake use than offroad riding, so your newly re-purposed offroad bike is going to see a lot more front brake use on the road. It's highly recommended to use a good quality racing brake fluid that will last longer and put up with the high heat demands of asphalt riding. This is even more crucial when building a supermoto for the track!